Patent application title: Hybrid Photovoltaic Cell Module

Abstract:

A hybrid photovoltaic cell module includes a substrate and a photopolymer
composition disposed on the substrate. The photopolymer composition
includes an organic photopolymer, a plurality of nanoparticles, and a
dendrimer that disperses the nanoparticles in the composition. The
dendrimer has a number average molecular weight of from 300 to 10,000
g/mol and a core having a carbon atom directly bonded to X1 and
X2 and two --CH2 groups. X1 is a hydrogen atom, a
functional group, or a chain including a functional group. X2 is a
chain including a functional group that is the same or different from the
functional groups of X1. Each --CH2 group is bonded to a chain
that independently includes a functional group that is the same or
different from said functional groups of X1 and X2. The module
is formed using a method that includes the step of disposing the
photopolymer composition on the substrate.

Claims:

1. A hybrid photovoltaic cell module comprising:A. a substrate; andB. a
photopolymer composition disposed on said substrate and comprising;(1) an
organic photopolymer,(2) a plurality of nanoparticles, and(3) a dendrimer
for dispersing said plurality of nanoparticles in said photopolymer
composition, wherein said dendrimer has a number average molecular weight
of from 300 to 10,000 g/mol and has a core having the general formula:
##STR00007## wherein X1 is a hydrogen atom, a functional group, or a
chain comprising a functional group;wherein X2 is a chain comprising
a functional group that is the same or different from said functional
groups of X1; andwherein each --CH2 group is bonded to a chain
and each chain independently comprises a functional group that is the
same or different from said functional groups of X1 and X.sup.2.

2. A hybrid photovoltaic cell module as set forth in claim 1 wherein said
dendrimer is free of covalent bonds to a fullerene.

3. A hybrid photovoltaic cell module as set forth in claim 1 wherein said
functional group of each chain bonded to said --CH2 groups is
independently selected from the group of an aliphatic functional group
having at least 4 carbon atoms, an alcohol functional group, and an ester
functional group.

4. A hybrid photovoltaic cell as set forth in claim 3 wherein said
functional group of X2 is selected from the group of an aliphatic
functional group having at least 4 carbon atoms, an alcohol functional
group, and an ester functional group.

5. A hybrid photovoltaic cell as set forth in claim 3 wherein said
functional group of X2 is selected from the group of a
nitrogen-containing functional group, a phosphorous-containing functional
group, a sulfur-containing functional group, and an oxygen-containing
functional group.

6. A hybrid photovoltaic cell as set forth in claim 4 wherein X2
further comprises two additional functional groups which are each the
same or different from said functional group of X2, and wherein each
of said two additional functional groups are independently selected from
the group of an aliphatic functional group having at least 4 carbon
atoms, an alcohol functional group, and an ester functional group.

7. A hybrid photovoltaic cell as set forth in claim 6 wherein X1 is
said chain and said functional group of said chain is selected from the
group of an aliphatic functional group having at least 4 carbon atoms, an
alcohol functional group, and an ester functional group.

8. A hybrid photovoltaic cell as set forth in claim 7 wherein said chain
further comprises two additional functional groups which are each the
same or different from said functional groups of X1 and wherein each
of said two additional functional groups are independently selected from
the group of an aliphatic functional group having at least 4 carbon
atoms, an alcohol functional group, and an ester functional group.

9. A hybrid photovoltaic cell as set forth in claim 1 wherein X1 is
said chain and said functional group of said chain is selected from the
group of an aliphatic functional group having at least 4 carbon atoms, an
alcohol functional group, and an ester functional group.

10. A hybrid photovoltaic cell as set forth in claim 9 wherein said chain
further comprises two additional functional groups which are each the
same or different from said functional groups of X1 and wherein each
of said two additional functional groups are independently selected from
the group of an aliphatic functional group having at least 4 carbon
atoms, an alcohol functional group, and an ester functional group.

11. A hybrid photovoltaic cell module as set forth in claim 1 wherein each
--CH2 group is directly bonded to an oxygen atom.

12. A hybrid photovoltaic cell module as set forth in claim 1 wherein each
--CH2 group is directly bonded to an oxygen atom and X2
comprises a --CH2--O group directly bonded to the central carbon
atom of said core.

13. A hybrid photovoltaic cell module as set forth in claim 12 wherein
X1 is said chain and said chain comprises a --CH2--O group
directly bonded to the central carbon atom of said core.

14. A hybrid photovoltaic cell module as set forth in claim 1 wherein
X1 is said chain and said chain comprises a --CH2--O group
directly bonded to the central carbon atom of said core.

15. A hybrid photovoltaic cell module as set forth in claim 1 wherein at
least one of said chains bonded to said --CH2 groups has the general
chemical structure: ##STR00008##

16. A hybrid photovoltaic cell module as set forth in claim 1 wherein both
chains bonded to said --CH2 groups have the general chemical
structure: ##STR00009##

17. A hybrid photovoltaic cell module as set forth in claim 16 wherein
X2 has the general chemical structure: ##STR00010##

18. A hybrid photovoltaic cell module as set forth in claim 1 wherein
X2 has the general chemical structure: ##STR00011##

19. A hybrid photovoltaic cell module as set forth in claim 1 wherein said
dendrimer has the general chemical structure: ##STR00012##

20. A hybrid photovoltaic cell as set forth in claim 19 wherein said
dendrimer is present in said photopolymer composition in a ratio of from
0.05:1 to 1:1 of said dendrimer to said organic photopolymer.

21. A hybrid photovoltaic cell as set forth in claim 1 wherein said
dendrimer is present in said photopolymer composition in a ratio of from
0.05:1 to 1:1 of said dendrimer to said organic photopolymer.

24. A hybrid photovoltaic cell module as set forth in claim 1 wherein said
substrate comprises a plastic.

25. A hybrid photovoltaic cell module as set forth in claim 24 further
comprising:A. a conducting composition disposed on and in direct contact
with said substrate;B. a primer comprising disposed on and in direct
contact with said conducting composition; andC. an electrode,wherein said
photopolymer composition is disposed on and in direct contact with said
primer and said electrode is disposed on and in direct contact with said
photopolymer composition.

27. A hybrid photovoltaic cell module as set forth in claim 26 wherein
said organic photopolymer is selected from the group of
poly(3-octylthiophene), poly(phenylenevinylene), poly(3-hexylthiophene),
polyanilines, and combinations thereof, and wherein said dendrimer has
the general chemical structure: ##STR00013##

28. A hybrid photovoltaic cell module as set forth in claim 27 wherein
said organic photopolymer is further defined as poly(3-hexylthiophene)
and said nanoparticles comprise titanium dioxide, wherein said
poly(3-hexylthiophene), said titanium dioxide, and said dispersant are
present in a weight ratio of about 1:1:0.25, wherein said module produces
a light absorbance of from between about 0.36 and 0.47 absorbance units
measured at a wavelength between about 400 and 700 nanometers, wherein
the light absorbance has a maximum measured at a wavelength between about
550 and 650 nanometers, and wherein the light absorbance is measured when
said photopolymer composition is at a thickness of about 100 micrometers
on said substrate.

29. A hybrid photovoltaic cell module as set forth in claim 28 that
produces a photoluminescence of from between about 1275 and 2300 photon
counts per second at a wavelength between 600 and 750 nanometers.

30. A hybrid photovoltaic cell module as set forth in claim 28 that has a
4 to 10 percent power conversion efficiency calculated according to the
formula η=Pmax/Po*A, wherein Pmax is a maximum power
of said module, Po is total solar irradiation striking said module,
and A is a surface area of said module.

31. A hybrid photovoltaic cell module as set forth in claim 1 wherein said
organic photopolymer, said nanoparticles, and said dispersant are present
in a weight ratio of about 1:1:0.25, wherein said module produces a light
absorbance of from between about and 0.47 absorbance units measured at a
wavelength between about 400 and 700 nanometers, wherein the light
absorbance has a maximum measured at a wavelength between about 550 and
650 nanometers, and wherein the light absorbance is measured when said
photopolymer composition is at a thickness of about 100 micrometers on
said substrate.

32. A method of forming a hybrid photovoltaic cell module comprising a
substrate and a photopolymer composition disposed on the substrate, said
method comprising the step of disposing the photopolymer composition on
the substrate, wherein the photopolymer composition comprises:(1) an
organic photopolymer,(2) a plurality of nanoparticles, and(3) a dendrimer
for dispersing the plurality of nanoparticles in the photopolymer
composition, wherein the dendrimer has a number average weight of from
300 to 10,000 g/mol and a core having the general formula: ##STR00014##
wherein X1 is a hydrogen atom, a functional group or a chain
comprising a functional group;wherein X2 is a chain comprising a
functional group that is the same or different from the functional groups
of X1; andwherein each --CH2 group is bonded to a chain and
each chain independently comprises a functional group that is the same or
different from the functional groups of X1 and X.sup.2.

33. A method as set forth in claim 32 wherein the dendrimer is free of
covalent bonds to a fullerene.

34. A method as set forth in claim 32 wherein at least one of the chains
bonded to the --CH2 groups has the general chemical structure:
##STR00015##

35. A method as set forth in claim 32 wherein the dendrimer has the
general chemical structure: ##STR00016##

36. A method as set forth in claim 35 wherein the step of disposing is
further defined as disposing the photopolymer composition on the
substrate using a printing apparatus.

37. A method as set forth in claim 35 wherein the step of disposing is
further defined as spraying the photopolymer composition on the
substrate.

38. A method as set forth in claim 35 wherein the hybrid photovoltaic cell
module further comprises an electrode disposed on the photopolymer
composition and the method further comprises the step of disposing the
electrode on the photopolymer composition via chemical vapor deposition.

39. A method as set forth in claim 35 wherein the hybrid photovoltaic cell
module further comprises a conducting composition disposed on and in
direct contact with said substrate, a primer disposed on and in direct
contact with said conducting composition, and an electrode, wherein the
photopolymer composition is disposed on and in direct contact with the
primer and said electrode is disposed on and in direct contact with said
photopolymer composition, wherein the step of disposing the photopolymer
composition is further defined as disposing the photopolymer composition
on the primer, and wherein the method further comprises the steps of:A.
disposing the conducting composition on the substrate;B. disposing the
primer on the conducting composition; andC. disposing the electrode on
the photopolymer composition.

40. A hybrid photovoltaic cell module comprising:A. a substrate; andB. a
photopolymer composition disposed on said substrate and comprising;(1) an
organic photopolymer,(2) a plurality of nanoparticles, and(3) a dendrimer
for dispersing said plurality of nanoparticles in said photopolymer
composition, wherein said dendrimer has a number average molecular weight
of from 300 to 10,000 g/mol, a polydispersity of from 1 to 1.2, and a
core having the general formula: ##STR00017## wherein each of X1 to
X4 is independently a hydrogen atom, a functional group, or a chain
comprising one or more functional groups that may be the same or
different from each other.

41. A hybrid photovoltaic cell module as set forth in claim 40 wherein
said dendrimer has a size of from 10 to 200 nanometers,

42. A hybrid photovoltaic cell module comprising:A. a substrate; andB. a
photopolymer composition disposed on said substrate and comprising;(1) an
organic photopolymer,(2) a plurality of nanoparticles, and(3) a dendrimer
for dispersing said plurality of nanoparticles in said photopolymer
composition, wherein said dendrimer has a number average molecular weight
of from 300 to 10,000 g/mol and has a core having the general formula:
##STR00018## wherein X1 is a hydrogen atom, a functional group, or a
chain comprising a functional group; andwherein each --CH2 group is
bonded to a chain and each chain independently comprises a functional
group that is the same or different from said functional groups of
X.sup.1.

43. A hybrid photovoltaic cell module as set forth in claim 42 wherein
said dendrimer is free of covalent bonds to a fullerene.

44. A hybrid photovoltaic cell module as set forth in claim 42 wherein
said functional group of each chain bonded to said --CH2 groups is
independently selected from the group of an aliphatic functional group
having at least 4 carbon atoms, an alcohol functional group, and an ester
functional group.

45. A hybrid photovoltaic cell as set forth in claim 42 wherein X1 is
said chain and said functional group of said chain is selected from the
group of an aliphatic functional group having at least 4 carbon atoms, an
alcohol functional group, and an ester functional group.

46. A hybrid photovoltaic cell as set forth in claim 45 wherein said chain
further comprises two additional functional groups which are each the
same or different from the functional groups of X1 and wherein each
of said two additional functional groups are independently selected from
the group of an aliphatic functional group having at least 4 carbon
atoms, an alcohol functional group, and an ester functional group.

[0002]The present invention generally relates to a hybrid photovoltaic
cell module. More specifically, the hybrid photovoltaic cell module
comprises a substrate and a photopolymer composition that includes a
dendrimer and that is disposed on the substrate. The present invention
also relates to a method of forming the photovoltaic cell module.

DESCRIPTION OF THE RELATED ART

[0003]Solar cells, also known as photovoltaic cells or "excitonic
photovoltaic cells," are semiconductor devices used to convert light into
electricity. Photovoltaic cell modules typically include substrates and
photovoltaic cells bonded to the substrates. The photovoltaic cell
modules are generally used in outdoor applications to collect light and
are commonly referred to as "solar panels." Photovoltaic cells and
photovoltaic cell modules perform two primary functions. A first function
is photogeneration of charge carriers such as electrons and holes in
light absorbing materials. The second function is direction of the charge
carriers to a conductive contact to transmit electricity.

[0004]As is known in the art, photovoltaic cells generate electricity
through light absorption, exciton dissociation, and charge transport. The
photovoltaic cells typically include semiconductors that collect and
absorb light and produce excitons. Excitons include bound states of
electrons and imaginary particles (electron holes) that are formed in the
semiconductors. Light typically enters the photovoltaic cells and strikes
the semiconductor thereby exciting electrons from valence bands of the
semiconductor into conduction bands of the semiconductor. The electrons
that move from the valence bands to the conductor bands leave behind
electron holes of opposite electric charge, to which the electrons are
attracted by Coulombic attraction forces. Ideally, the electrons
dissociate from the electron holes through charge transport with
conductive contacts that are less than 10 nm from the electrons. This
generates electricity and current flow. If the electrons and the electron
holes recombine (exciton recombination) or if the semiconductor is
restored to its original oxidation level (back electron transfer),
generation of electricity is reduced and efficiency of the photovoltaic
cell is reduced, as shown in FIG. 1.

[0005]There are four general types (i.e., generations) of photovoltaic
cells that are known in the art. First generation photovoltaic cells
typically include single crystal and/or polycrystalline silicon or other
inorganic molecules. These types of photovoltaic cells are used in a
majority of photovoltaic cell applications and have efficiencies up to
about ˜31% by Shockley Queisser limit. However, these types of
photovoltaic cells are expensive to produce due to an inherent cost of
processing, handling silicon, and fabrication.

[0006]Second generation photovoltaic cells, also known as thin film cells,
are typically based on thin epitaxial deposits of semiconductors on
lattice-matched wafers. These semi-conductors usually include amorphous
silicon, polycrystalline silicon, micro-crystalline silicon, cadmium
telluride, and copper indium selenide/sulfide. Theoretically, thin film
cells have reduced mass, as compared to their first generation
counterparts, thereby allowing these cells to be used with light and
flexible materials. They can also be formed at low cost and with relative
manufacturing ease. However, the second generation photovoltaic cells are
not as efficient (˜9% efficiency) as the first generation
photovoltaic cells.

[0007]Third and fourth generation photovoltaic cells are typically based
on organic photopolymers and are also known as "hybrid photovoltaic
cells." The organic photopolymers act as "pseudo-semiconductors" and
conduct electricity. The third generation photovoltaic cells can be
produced at a lower cost than the first and second generation
photovoltaic cells, can be more easily formed into specific shapes and
sizes, and are typically lighter than their counterparts. However, the
third generation photovoltaic cells typically exhibit poor efficiency of
from 1-3%.

[0008]Fourth generation photovoltaic cells typically include organic
photopolymers and also typically includes nanoparticles such as quantum
dots and carbon nanotubes, which increase the efficiency and performance
of these photovoltaic cells. More specifically, fourth generation
photovoltaic cells that include quantum dots and carbon nanotubes can be
more efficient as compared to third generation photovoltaic cells but
still have a maximum efficiency of about 5-6%. Quantum dots allow for
multiple exciton generation which increases an amount of light absorbed.
Carbon nanotubes increase a conversion efficiency and electrical
conductivity of the photovoltaic cells by conducting electrons away from
the organic photopolymers and thereby reducing exciton recombination.
However, when used in these types of photovoltaic cells, the
nanoparticles tend to agglomerate and are not maximally efficient, as
shown in FIGS. 2 and 3.

[0009]The aforementioned photovoltaic cells vary in efficiency,
usefulness, and cost. Although the third and fourth generation
photovoltaic cells typically are lighter and more flexible that their
counterparts, these photovoltaic cells are not as efficient as the first
generation photovoltaic cells. Thus, there remains an opportunity to
develop an improved hybrid photovoltaic cell that is both efficient and
useful. There also remains an opportunity to develop such a hybrid
photovoltaic cell in a cost effective manner.

SUMMARY OF THE INVENTION AND ADVANTAGES

[0010]The instant invention provides a hybrid photovoltaic cell module
that includes a substrate and a photopolymer composition disposed on the
substrate. The photopolymer composition includes an organic photopolymer,
a plurality of nanoparticles, and a dendrimer that disperses the
plurality of nanoparticles in the photopolymer composition. The dendrimer
has a number average molecular weight of from 300 to 10,000 g/mol and a
core having the general formula:

##STR00001##

In this formula, X1 is a hydrogen atom, a functional group, or a
chain including a functional group. Also in this formula, X2 is a
chain including a functional group that is the same or different from the
functional groups of X1. Furthermore, each --CH2 group of the
core is bonded to a chain. Each chain independently includes a functional
group that is the same or different from said functional groups of
X1 and X2. The hybrid photovoltaic cell module is formed using
a method that includes the step of disposing the photopolymer composition
on the substrate.

[0011]The dendrimer in the photopolymer composition interacts with the
organic photopolymer and the plurality of nanoparticles thereby
maximizing homogeneous distribution of the nanoparticles within the
photopolymer composition. Increased homogeneous distribution, i.e.,
increased dispersion of the plurality of nanoparticles, amplifies light
absorption, exciton dissociation, and charge transport and leads to
increased light conversion efficiency. Additionally, the dendrimer
minimizes exciton recombination and back electron transfer which also
contributes to the increased efficiency. Overall, the dendrimer allows
the hybrid photovoltaic cell module to exhibit a greater than 50%
increase in light conversion efficiency as compared to its predecessors.
The hybrid photovoltaic cell module also has a minimized weight, is
produced with decreased production costs, and operates over a wide range
of temperatures and in a variety of radiation environments.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0012]Other advantages of the present invention will be readily
appreciated, as the same becomes better understood by reference to the
following detailed description when considered in connection with the
accompanying drawings wherein:

[0014]FIG. 2 is an electron scanning micrograph at 60,000 times
magnification showing a prior art photopolymer composition including a
plurality of nanoparticles (e.g. quantum dots and carbon nanotubes) that
are agglomerated resulting in poor light conversion efficiency;

[0015]FIG. 3 is the electron scanning micrograph of FIG. 2 shown at
160,000 times magnification;

[0016]FIG. 4 is an electron scanning micrograph at 60,000 times
magnification showing the instant photopolymer composition including a
plurality of nanoparticles (e.g. quantum dots and carbon nanotubes) that
are homogeneously dispersed in the photopolymer composition by the
instant dendrimer resulting in increased light conversion efficiency;

[0017]FIG. 5 is the electron scanning micrograph of FIG. 4 shown at
160,000 times magnification;

[0018]FIG. 6 is a line graph illustrating increased light absorbance
(absorbance units) of the instant photopolymer composition including
poly(3-hexylthiophene), titanium dioxide, and the dispersant of this
invention in a weight ratio of about 1:1:0.25, as compared to the same
photopolymer composition without the dendrimer, as a function of
wavelength;

[0019]FIG. 7 is a line graph illustrating increased photoluminescence
(photon counts per second) of the instant photopolymer including
poly(3-hexylthiophene), titanium dioxide, and the dispersant of this
invention in a weight ratio of about 1:1:0.25, as compared to the same
photopolymer composition without the dendrimer, as a function of
wavelength;

[0020]FIG. 8 illustrates various non-limiting embodiments of the central
core of the dendrimer of the instant invention;

[0021]FIG. 9 illustrates various non-limiting embodiments of X1,
X2, and/or the chains of the dendrimer of the instant invention;

[0022]FIG. 10a illustrates one non-limiting embodiment of the dendrimer of
the instant invention;

[0023]FIG. 10b illustrates another non-limiting embodiment of the
dendrimer of the instant invention;

[0024]FIG. 10c illustrates yet another non-limiting embodiment of the
dendrimer of the instant invention;

[0025]FIG. 10d illustrates still another non-limiting embodiment of the
dendrimer of the instant invention;

[0026]FIG. 10e illustrates yet another non-limiting embodiment of the
dendrimer of the instant invention;

[0027]FIG. 10f illustrates the dendrimer of FIG. 10e including
stereochemistry;

[0029]FIG. 12 is a side view of a first hybrid photovoltaic cell module of
the instant invention including the substrate and the photopolymer
composition disposed on the substrate;

[0030]FIG. 13 is a side view of a second hybrid photovoltaic cell module
of the instant invention including a plastic substrate, a conducting
composition disposed on the substrate, a primer disposed on the
conducting composition, the instant photopolymer composition disposed on
the primer, and an electrode disposed on the photopolymer composition;
and

[0031]FIG. 14 is a side view of a third hybrid photovoltaic cell module of
the instant invention including a substrate, the instant photopolymer
composition disposed on the substrate, and an electrode disposed on the
photopolymer composition.

DETAILED DESCRIPTION OF THE INVENTION

[0032]The present invention provides a hybrid photovoltaic cell module
(20) (hereinafter referred to as "module") generally shown in FIGS. 12-14
and a method of forming the module (20). As is known in the art, modules
(20) typically include silicon. Thus, the terminology "hybrid," as used
herein, means that the module (20) includes at least one organic
photopolymer, as described in detail below. It is contemplated that the
module (20) may include silicon or may be free of silicon. Typically, the
module (20) is free of silicon such as amorphous silicon, monocrystalline
silicon, polycrystalline silicon, microcrystalline silicon, and
nanocrystalline silica

[0033]The module (20) can be used in any industry including, but not
limited to, electronics, power generation systems, satellites,
automobiles, batteries, photoelectrochemical applications, polymer solar
cell applications, nanocrystal solar cell applications, and
dye-sensitized solar cell applications. In one embodiment, a series of
modules (20) are electrically connected and form a photovoltaic array.
Photovoltaic arrays are typically used on rooftops or in automobiles and
may be connected to battery backups and/or DC pumps. The photovoltaic
array of the instant invention may be planar or non-planar and typically
functions as a single electricity producing unit wherein the modules (20)
are interconnected in such a way as to generate voltage, such as in a
parallel circuit.

[0034]Referring specifically to the module (20), the module (20) includes
a substrate (22) which may include any suitable material known in the
art. The substrate (22) may provide protection to a front and/or rear
surface of the module (20). The substrate (22) may be of any rigidity and
may be soft or stiff, flexible or rigid. Alternatively, the substrate
(22) may simultaneously include rigid and flexible segments. The
substrate (22) may be transparent to light, impervious to light, or may
be opaque. In one embodiment, the substrate (22) includes glass.
Alternatively, the substrate (22) may include one or more plastics, metal
foils, polyimides, polyesters, polyolefins, nylons, polycarbonates,
polyamides, ethylene-vinyl acetate copolymers, organic fluoropolymers,
spin castable or moldable plastics, and combinations thereof.

[0035]The substrate (22) may be load bearing or non load bearing and may
be included in any portion of the module (20). Typically, the substrate
(22) is load bearing. The substrate (22) may be a top and outermost layer
and/or a bottom and outermost layer of the module (20). Alternatively,
the substrate (22) may be an interior layer. Bottom layers typically
serve as mechanical support for the module (20), as shown in FIGS. 12-14.
Alternatively, the module (20) may include a substrate (22) and a second
substrate (not shown). The second substrate may be the same or different
than the substrate (22). In one embodiment, the substrate (22) is the
bottom layer and the second substrate is a top layer (e.g. a
superstrate). Typically, at least one of the substrates is transparent to
sunlight and is positioned in front of a light source. The substrate (22)
may provide protection from environmental conditions such as rain, snow,
and heat. The substrate (22) may also include a protective layer of
polypropylene or polybutylene disposed thereon.

[0036]In addition to the substrate (22), the module (20) also includes a
photopolymer composition (24) disposed on the substrate (22). The
photopolymer composition (24) may be disposed on the substrate (22) and
be in direct contact with the substrate (22) or be spaced apart from
(i.e., not in direct contact with) the substrate (22) while remaining
"disposed on" the substrate (22). The module (20) may include multiple
layers of the photopolymer composition (24), e.g. first and second and/or
third layers of the photopolymer composition (24). Second, third, and/or
any additional layers of the photopolymer composition (24) may be the
same or different from the photopolymer composition (24) described above.
The additional layers of the photopolymer composition (24) may also be
disposed on the substrate (22). In various embodiments, the photopolymer
composition (24) and/or any additional layers of the photopolymer
composition (24) are present in a thickness of from 0.1 to 200
micrometers, of from 1 to 100 micrometers, of from 1 to 75 micrometers,
of from 1 to 50 micrometers, of from 10 to 75 micrometers, of from 10 to
50 micrometers, of from 10 to 40 micrometers, of from 10 to 30
micrometers, of from 10 to 20 micrometers, of from 20 to 50 micrometers,
of from 20 to 40 micrometers, or of from 20 to 30 micrometers. In one
embodiment, the photopolymer composition (24) is disposed on the
substrate (22) in a thickness of from about 0.1 to about 3 mils. Without
intending to be bound by any particular theory, it is believed that
minimizing the thickness of the photopolymer composition (24) may
maximize efficiency of the module (20). Of course, the instant invention
is not limited to the aforementioned thicknesses.

[0037]The photopolymer composition (24) may be transparent to UV and/or
visible light while any second (or additional) layers of the photopolymer
composition (24) may be transparent to light, impermeable to light or
opaque. The photopolymer composition (24) may be disposed on the
substrate (22) in any amount and size. The photopolymer composition (24)
includes an organic photopolymer, a plurality of nanoparticles, and a
dendrimer. In one embodiment, the photopolymer composition (24) consists
essentially of the organic photopolymer, the plurality of nanoparticles,
and the dendrimer and does not include any compounds that materially
affect the basic and novel characteristic of the photopolymer composition
(24) and/or the module (20) such as metals. In another embodiment, the
photopolymer composition (24) consists of the organic photopolymer, the
plurality of nanoparticles, and the dendrimer.

[0038]Referring to the organic photopolymer, the terminology
"photopolymer" includes any organic polymer that generates electrons when
struck with light energy, whether visible, infrared, UV, IR, etc. In one
embodiment, the organic photopolymer is selected from the group of
poly(3-octylthiophene), poly(phenylenevinylene), poly(3-hexylthiophene),
polyanilines, and combinations thereof. Preferably, the organic
photopolymer includes poly(3-hexylthiophene). Of course, the instant
invention is not limited to these photopolymers and may include any
organic photopolymer known in the art. The photopolymer composition (24)
typically includes the organic photopolymer in an amount of from 1 to 99
parts by weight per 100 parts by weight of the photopolymer composition.
In other embodiments, the organic photopolymer is present in amounts of
from 1 to 99.9, from 2 to 98, from 3 to 97, from 4 to 96, from 5 to 95,
from 6 to 94, from 7 to 93, from 8 to 92, from 9 to 91, or from 10 to 90,
parts by weight per 100 parts by weight of the photopolymer composition
(24).

[0039]Referring now to the plurality of nanoparticles, it is believed that
the chemical composition and size of the nanoparticles determine what
types (i.e., wavelengths) of light are absorbed by the module (20).
Typically, the organic photopolymer and/or the photopolymer composition
(24) is "doped" with the nanoparticles. The plurality of nanoparticles
may include inorganic nanoparticles, organic nanoparticles, and
combinations thereof. In one embodiment, the plurality of nanoparticles
consists essentially of inorganic nanoparticles and does not include
organic nanoparticles. In another embodiment, the plurality of
nanoparticles consists of inorganic nanoparticles. In yet another
embodiment, the plurality of nanoparticles consists essentially of
organic nanoparticles and does not include inorganic nanoparticles. In
still another embodiment, the plurality of nanoparticles consists of
organic nanoparticles. Typically, the plurality of nanoparticles includes
both inorganic and organic nanoparticles. In various embodiments, the
plurality of nanoparticles includes inorganic and/or organic
nanoparticles are independently present in amounts of less than 50, more
typically in amounts of less than 20, still more typically in amounts of
less than 10, and most typically in amounts of less than 5, parts by
weight per 100 parts by weight of the photopolymer composition (24).

[0040]In other embodiments, the plurality of nanoparticles is present in
amounts of from 0.1 to 10, from 1 to 10, from 2 to 10, from 1 to 5, or
from 2 to 5, parts by weight per 100 parts by weight of the photopolymer
composition (24). In still other embodiments, the plurality of
nanoparticles includes inorganic and organic nanoparticles that are
present in a ratio of from 0.05:1 to 1:2, in a ratio of 0.1:1, in a ratio
of 1:2, in a ratio of 1:5, in a ratio of 1:10, in a ratio of 1:1, or in
any ratio therebetween the aforementioned values. Each of the
aforementioned ratios is of the inorganic nanoparticles to the organic
nanoparticles.

[0041]In one embodiment, the inorganic nanoparticles are selected from the
group of titanium dioxide (TiO2), cadmium sulfide (CaS), cadmium
selenide (CaSe), cadmium telluride (CdTe) and combinations thereof. In
other embodiments, the inorganic nanoparticles may include, but are not
limited to, CuInS2, TiO2, CdTe, ZnO, Al2O3,
Fe2O3, Ge0, SiC, SrTiO3, InP, CdSe, CdS, PbS, and
combinations thereof. The inorganic nanoparticles may be further defined
as quantum dots. As is known in the art, quantum dots are semiconductor
nanostructures that confine motion of conduction band electrons, valence
band holes, and/or excitons (i.e., bound pairs of conduction band
electrons and valence band holes) in three spatial directions. Typically,
the quantum dots include finite numbers (from 1-100) of conduction band
electrons, valence band holes, or excitons, and thereby have a finite
number of elementary electric charges. Most typically, the quantum dots
include nano-sized TiO2. Preferably, the quantum dots have a band
gap of from 0.7 to 3.8 eV and most preferably of about 1.5 eV to optimize
light absorption and electricity production. The quantum dots also
preferably range in size of from 1 to 600 nanometers. Of course, the
instant invention is not limited to the aforementioned inorganic
nanoparticles and may include any inorganic nanoparticles known in the
art.

[0042]Referring now to the organic nanoparticles, these nanoparticles
typically include carbon nanotubes (CNTs). Carbon nanotubes are
allotropes of carbon that have a nanostructure in which a
length-to-diameter ratio exceeds 1,000,000. As known in the art, carbon
nanotubes are typically cylindrical fullerenes having at least one end
capped with a hemisphere of a "buckyball." Carbon nanotubes can range in
size from nanometers to millimeters and may be single walled or
multi-walled. Other allotropic forms of nano-sized carbon such as
fullerenes and carbon sheets, etc may also be used. Without intending to
be bound by any particular theory, it is believed that, in this
invention, the organic photopolymer acts as an electron donor while the
plurality of nanoparticles act as electron acceptors, thus allowing an
electrical current to be generated. More specifically, it is believed
that the organic photopolymer of the instant invention produces
electron-hole pairs. The carbon nanotubes are believed to transport the
electrons away from the holes to minimize recombination and generate a
photovoltaic effect. Of course, the instant invention is not limited to
the aforementioned organic nanoparticles and may include any organic
nanoparticles known in the art. Without intending to be bound by any
particular theory, it is believed that increased efficiency and
absorption of the module of this invention can be attributed, at least in
part, to distribution and interaction between the plurality of
nanoparticles and the photopolymer composition (24). It is believed that
the presence of the plurality of nanoparticles lowers the absorption of
the photopolymer composition (24) due to a disordered matrix. Improved
ordering is believed to maintain interactions among polymer chains and
improve absorption effectiveness of this invention.

[0043]In various embodiments, the photopolymer composition (24) is free
of, or substantially free of, fullerenes such as Buckey Balls. In one
embodiment, the photopolymer composition is entirely free of fullerenes.
In another embodiment, the terminology "substantially free of" refers to
an amount of fullerenes present in the photopolymer composition (24) of
less than 500, more typically of less than 100, still more typically of
less than 50, and most typically of less than 10, parts by weight per one
million parts by weight of the photopolymer composition (24). In other
embodiments, the photopolymer composition (24) includes fullerenes but
the dendrimer is not covalently bonded to any of the fullerenes.

[0044]In one alternative embodiment, the dendrimer is free of covalent
bonds to a fullerene. In another alternative embodiment, the central core
of the dendrimer is free of covalent bonds to a fullerene. In still other
embodiments, the central core of the dendrimer and/or one or more
"chains" of the dendrimer is covalently bonded to a fullerene. As is
known in the art, and as used in the instant invention, the terminology
"fullerene" includes a family of carbon allotropes in the form of hollow
spheres, ellipsoids, tubes, and/or plane, as is known in the art.

[0045]Referring now to the dendrimer, the terminology "dendrimer" refers
to a repeatedly branched molecule. Dendrimers may also be known as
cascade type molecules or arborols. Typically, dendrimers are repeatedly
branched, approximately monodisperse, and highly symmetric compounds.
Dendrimers can be formed by any process known in the art but are
typically formed in one of two ways. A first way is known in the art as a
"divergent" method and includes successively attaching one branching unit
after another to the core to achieve a multiplication of peripheral
groups. Typically, this first way is limited by steric effects. The
second way, also known in the art as a "convergent" method includes
constructing the dendrimer from outside in, i.e., from end groups towards
the core. The dendrimer of the instant invention may be formed by one or
both aforementioned methods and/or by any other method known in the art.
In one embodiment, the dendrimer is further defined as a star-polymer and
is preferably highly branched. In the instant invention, the dendrimer is
also known as a "dispersant dendrimer" and is thought to disperse the
plurality of nanoparticles within the photopolymer composition (24).

[0046]Preferably, the dendrimer has nano-scale dimensions. In various
embodiments, the dendrimer has an approximately spherical
three-dimensional structure and has an approximate diameter of from 10 to
200, from 30 to 100, or from 50 to 100, nanometers. In other embodiments,
the dendrimer has an approximately conical three-dimensional structure,
and has an approximate height of from 10 to 200, from 30 to 100, or from
50 to 100, nanometers, as measured from an apex of the cone to an arc of
the cone. In still other embodiments, the dendrimer has an approximate
length of from 10 to 200, from 30 to 100, or from 50 to 100, nanometers,
as measured from one end of the dendrimer to another.

[0047]The dendrimer of the instant invention has a central core (i.e., a
core). Typically, the core includes a tertiary or quaternary central
carbon atom. However, it is contemplated that the central carbon atom may
be a secondary carbon atom. In one embodiment, the core has the following
general formula:

##STR00002##

In this embodiment, X1 is a hydrogen atom, a functional group, or a
chain including a functional group. Also in this embodiment, X2 is a
chain including a functional group that is the same or different from the
functional groups of X1. Furthermore, in this embodiment, each
--CH2 group of the central core is bonded to a chain. Each chain in
this embodiment independently includes a functional group that is the
same or different from the functional groups of X1 and X2.

[0048]In another embodiment, the core has the following general formula:

##STR00003##

In this embodiment, X1 is a hydrogen atom, a functional group, or a
chain including a functional group. Furthermore, in this embodiment, each
--CH2 group is bonded to a chain and each chain independently
comprises a functional group that is the same or different from the
functional groups of X1.

[0049]In still another embodiment, the dendrimer has a number average
molecular weight of from 300 to 10,000 g/mol, a polydispersity of from 1
to 1.2, and a core having the general formula:

##STR00004##

[0050]wherein each of X1 to X4 is a hydrogen atom, a functional
group, or a chain comprising one or more functional groups that may be
the same or different from each other.

[0051]The functional group(s) of X1, X2, X3, X4,
and/or the chains may be any known in the art. The functional group(s)
typically include, but are not limited to, alkanes, alkene, alkynes,
benzene derivatives, toluene derivatives, haloalkanes, acyl halides,
anhydrides, alcohols, ketones, aldehydes, carbonates, carboxylates,
carboxylic acids, ethers, esters, peroxides, amides, amines, imines,
imides, azides, azo compounds, cyanates, isocyanates, nitrates, nitro
compounds, nitroso compounds, pyridine derivatives, phosphines,
phosphodiesters, phosphonic acid, phosphates, sulfides, sulfones,
sulfonic acid, sulfoxides, thiols, thiocyanates, disulfides, and
combinations thereof. In various embodiments, one or more of the
functional group(s) of X1, X2, X3, X4, and/or the
chains are selected from the group of a nitrogen-containing functional
group, a phosphorous-containing functional group, a sulfur-containing
functional group, and an oxygen-containing functional group. In another
embodiment, one or more of the functional group(s) of X1, X2,
X3, X4, and/or the chains are independently selected from the
group of an aliphatic functional group having at least 4 carbon atoms, an
alcohol functional group, and an ester functional group. It is
contemplated in this invention that an alcohol functional group may be
represented at R--OH wherein R may be a carbonyl group or a
saturated/unsaturated carbon atom. In other words, the dendrimer may
include an --OH group attached to a carbonyl carbon (C═O). This type
of alcohol functional group is also known as a carboxylic acid.
Alternatively, the alcohol functional group may be represented as R--O
and may not include an attached hydrogen atom. Typically, the alcohol
functional group includes --OH and is also known in the art as a hydroxyl
group.

[0052]In one embodiment, the functional group of each chain bonded to the
--CH2 groups of the core is independently selected from the group of
an aliphatic functional group having at least 4 carbon atoms, an alcohol
functional group, and an ester functional group. In another embodiment,
the functional group of X2 is selected from the group of an
aliphatic functional group having at least 4 carbon atoms, an alcohol
functional group, and an ester functional group. In still another
embodiment, the functional group of X2 is selected from the group of
a nitrogen-containing functional group, a phosphorous-containing
functional group, a sulfur-containing functional group, and an
oxygen-containing functional group. In still other embodiments, one or
more of the X1, X2, and/or the chains are further comprise two
additional functional groups which are each the same or different from
the functional group of X2. In one embodiment, each of the two
additional functional groups of X2 are independently selected from
the group of an aliphatic functional group having at least 4 carbon
atoms, an alcohol functional group, and an ester functional group. In a
further embodiment, X1 is a chain, as described above, and the
functional group of the chain is selected from the group of an aliphatic
functional group having at least 4 carbon atoms, an alcohol functional
group, and an ester functional group. In another embodiment, the chain
(of X1) further comprises two additional functional groups which are
each the same or different from the functional groups of X1. In this
embodiment, each of the two additional functional groups are
independently selected from the group of an aliphatic functional group
having at least 4 carbon atoms, an alcohol functional group, and an ester
functional group.

[0053]In one alternative embodiment, each --CH2 group is directly
bonded to an oxygen atom, as set forth in FIG. 8. In another alternative
embodiment, each --CH2 group is directly bonded to an oxygen atom
and X2 includes a --CH2--O group directly bonded to the central
carbon atom of the core, as also set forth in FIG. 8. In still another
embodiment, X1 is a chain and the chain includes a --CH2--O
group directly bonded to the central carbon atom of the core. In yet
another embodiment, at least one of the chains bonded to the --CH2
groups has the general chemical structure:

##STR00005##

[0054]In various embodiments, it is contemplated that that both and/or all
of the chains bonded to the --CH2 groups and/or any chains of
X1 and X2 may be, or may include, the general chemical
structures set forth in FIG. 9. Of course, the instant invention is not
limited to these chemical structures. It is also contemplated that both
and/or all of the chains bonded to the --CH2 groups have the
aforementioned general chemical structure, as set forth in FIG. 10. In
one alternative embodiment, X2 has the aforementioned general
chemical structure. In still another embodiment, dendrimer has the
following general chemical structure, as also set forth in FIG. 10:

##STR00006##

In one embodiment, the dendrimer has the general chemical structure,
including stereochemistry, as set forth in FIG. 10f.

[0055]Typically, the dendrimer includes hydroxyl groups, ester groups,
and/or alkyl groups. In one embodiment, the dendrimer includes one or
more hydroxyl groups, thiol groups, amine (NH2) groups, and/or acid
groups. In another embodiment, the dendrimer has multiple chains and at
least two of the chains are conductive resulting from polyaniline or
poly-3-hexylthiophene chain attachments. In still another embodiment, the
dendrimer includes one or more chains bonded to an electrically
conducting compound such as poly(3,4-ethylene dioxy thiophene) (PEDOT) or
a polyaniline. Typically, electrically conducting compounds have
unsaturation and aromatic character.

[0056]The dendrimer has a number average molecular weight of from 300 to
10,000, more typically of from 300 to 4,000, still more typically of from
500 to 3,000, even more typically of from 500 to 1,500, and most
typically of from 1,000 to 1,500 g/mol. The dendrimer also typically has
a weight average molecular weight of from 350 to 12,000, more typically
of from 350 to 4,800, still more typically of from 600 to 3,600, even
more typically of from 600 to 1,800, and most typically of from 1,200 to
1,800, g/mol. The dendrimer also typically has a polydispersity of from 1
to 1.5, more typically of from 1 to 1.4, still more typically of from 1
to 1.3, and most typically of from 1 to 1.2. In various embodiments, the
dendrimer is present in an amount of from 0.1 to 10, from 1 to 10, from 2
to 10, from 1 to 5, or from 2 to 5, parts by weight per 100 parts by
weight of the photopolymer composition (24). In one embodiment, the
dendrimer is present in the photopolymer composition (24) in a ratio of
from 0.05:1 to 1:1 of the dendrimer to the organic photopolymer.

[0057]It is believed that the dendrimer interacts with (e.g. "binds") the
plurality of nanoparticles through Van Der Waals attractions and
homogeneously disperses the plurality of nanoparticles in the
photopolymer composition (24), as shown in FIGS. 4 and 5. It is also
believed that polar functional groups (e.g. hydroxyl, thiol, amine, and
acid groups) of the dendrimer interact with inorganic nanoparticles and
increase the efficiency of the instant invention. It is further believed
that non-polar groups (e.g. carbon, aliphatic, aromatic, and cyclic
groups) of the dendrimer interact with the organic photopolymer and the
organic nanoparticles and also increase the efficiency of the instant
invention.

[0058]It is also believed that the dendrimer reduces and potentially
avoids flocculation of the plurality of nanoparticles through both steric
and electrostatic repulsion. The dendrimer may form a type of envelope
around the plurality of nanoparticles to more completely disperse the
nanoparticles in the photopolymer composition (24) while maintaining a
polymer network. Preferably, the plurality of nanoparticles are optimally
dispersed in the photopolymer composition (24) while maintaining a
continuous network in both organic (e.g. organic photopolymer) and
inorganic (e.g. quantum dots) phases.

[0059]Most preferably, the dendrimer has similar dimensional
characteristics (sizes) as the plurality of nanoparticles to maintain
nano-level morphology and increase homogeneous dispersion of the
plurality of nanoparticles in the photopolymer composition (24). Without
intending to be bound by any particular theory, it is believed that when
the sizes of the dendrimer and the nanoparticles are similar and less
than 200 nanometers, as first introduced and described above, increased
efficiency of the instant module (22) is achieved. It is believed that
similar sizes of the dendrimer and the nanoparticles results in less
steric interactions and limitations and allows the nanoparticles to be
more effectively and homogeneously dispersed within the photopolymer
composition (24). Typically, the organic photopolymer of the photopolymer
composition (24) is not nano-sized, i.e., does not have a size less than
200 nanometers in length, width, height, or diameter.

[0060]Preferably, the chains of the dendrimer at least partially envelope
the plurality of nanoparticles resulting in increased interaction,
increased dispersion of the plurality of nanoparticles in the
photopolymer composition (24), and increased conductivity of the
photopolymer composition (24). More specifically, the polar functional
groups of the dendrimer may interact with the inorganic nanoparticles
while the non-polar functional groups may interact with the organic
nanoparticles and the photopolymer.

[0061]In one embodiment, the dendrimer is formed by modifying a
dendrimeric or hyper-branched alcohol. Suitable alcohols can be
synthesized or commercially purchased from Perstorp Polyols of Perstorp,
Sweden. Typically, the dendrimeric or hyper-branched alcohols are
modified to add both polar and non-polar functional groups, such as those
described above. One of skill in the art may adjust these modifications
based on functionality of the organic photopolymer to ensure maximum
compatibility between the dendrimer, the plurality of nanoparticles, and
the organic photopolymer. One of skill in the art can customize addition
of non-polar groups to maximize Van der Waal interactions between the
plurality of nanoparticles and the dendrimer.

[0062]It is contemplated that the dendrimer may be formed by reacting
pentaerythritol and one or more aromatic, cycloaliphatic and/or aliphatic
anhydrides such as hexahydrophthalic anhydride, phthalic anhydride,
succinic anhydride and the like, with 2,3-epoxypropyl neodecanoate,
commercially available under the trade name Cardura-N. In one embodiment,
the dendrimer formed by the reaction described immediately above is
further reacted with additional anhydrides and extended with Cardura-N.
In another embodiment, the dendrimer is modified by converting some
alcohol functionalities to silyl, perfluoroalkyl, thiol, and/or thioalkyl
functionalities.

[0063]As set forth in FIG. 13, the module (20) may include a conducting
composition (26), different from the photopolymer composition (24),
disposed on the substrate (22). The conducting composition (26) may be in
direct or indirect contact with the substrate (22). In one embodiment,
the conducting composition (26) is in direct contact with the
photopolymer composition (24) and is disposed on the substrate (22). The
conducting composition (26) may include any compound known in the art
that is electrically conductive. In one embodiment, the conducting
composition (26) includes indium tin oxide (ITO) and may be transparent,
opaque, or impervious to light. It is believed that conducting
compositions (26) typically have good electron hole conductivity and can
be good electron donors. Thus, any electron donating material with good
electron conductivity can be used in this invention as the conducting
composition (26). In another embodiment, the conducting composition (26)
includes one or more of carbon nanotubes (CNT) containing coatings
developed by Elkos and Unidym, poly(3,4-ethylene dioxy thiophene)
protected by a UV absorbing layer, a mixture of poly(3,4-ethylene dioxy
thiophene) and poly(styrene sulphonate) protected by a UV absorbing
layer, aluminum doped ZnO developed by Angela Balchar of MIT, and
combinations thereof.

[0064]As further set forth in FIG. 13, the module (20) may also include a
primer (28) disposed on the substrate (22). The primer (28) may be in
direct or indirect contact with the substrate (22). In one embodiment,
the primer (28) is in direct contact with the conducting composition (26)
and is disposed on the substrate (22). The primer (28) may be any known
in the art. In one embodiment, the primer (28) includes a copolymer of
poly(3,4-ethylene dioxy thiophene) and poly(styrene sulphonate)
(PEDOT:PSS). In another embodiment, the primer (28) includes the CNT
containing coating described above. Typically, the primer (28) is applied
to the conducting composition (26) to reduce surface imperfections and
minimize electrical shorts. The primer (28) may be transparent, opaque,
or impervious to light. In one embodiment, the primer (28) has a higher
work function (5.0 eV) than the conducting composition (26). The higher
work function may facilitate transfer of holes from a highest occupied
molecular orbital of the photopolymer composition (24), e.g.
poly-(3-hexylthiophene), and may improve charge transport between the
photopolymer composition (24) and the conducting composition (26). In
various embodiments, the dendrimer includes one or more chains bonded to
an electrically conducting compound such as poly(3,4-ethylene dioxy
thiophene) (PEDOT) or a polyaniline which may eliminate a need for the
primer (28) and/or conducting composition (26).

[0065]The module (20) may also include an electrode (30) disposed on the
substrate (22). The electrode (30) may be in direct or indirect contact
with the substrate (22). In one embodiment, the electrode (30) is in
direct contact with the photopolymer composition (24) and is disposed on
the substrate (22). The electrode (30) may be any known in the art and
preferably includes metal. Alternatively, the electrode may include
organic or inorganic compounds that are conductive. In one embodiment,
the electrode (30) is a closely placed bundle of nano-conductors grown on
the substrate (22). These nano-conductors/electrode may tie to a single
conductor for connection to an outside circuit. The electrode can be
transparent, semi-transparent, or opaque.

[0066]Referring back to the module (20), in one embodiment, the module
(20) includes a flexible plastic substrate (22) and a conducting
composition (26) including ITO disposed thereon. In this embodiment, the
module (20) also includes the primer (28) including poly(3,4-ethylene
dioxy thiophene) and poly(styrene sulphonate) disposed on the conducting
composition (26). In this embodiment, the module (20) also includes a
photopolymer composition (24) including poly(3-hexylthiophene), carbon
nanotubes, titanium dioxide quantum dots, and the dendrimer. Further, the
module (20) also preferably includes an aluminum electrode (30) disposed
on the substrate (22). Preferably, the photopolymer composition (24) is
disposed within 10 nm of the substrate (22), if conductive, or within 10
nm of the conducting composition (26) to maximize exciton generation and
exciton dissociation, as shown in FIG. 9 and FIG. 11. This distance is
typically known as an exciton diffusion length.

[0067]Typically, electrons formed in the photopolymer along with positive
holes are conducted away from those holes. In theory, it is believed that
electron recombination is maximized if the exciton diffusion length (also
known as percolation length) is less than 10 nm. It is also believed that
a presence of carbon nanotubes inhibits electron recombination by
effectively providing a path for the electrons to move away from the
holes.

[0068]It is also contemplated that the module (20) may be fabricated by
incorporating electrical connects to an outer circuit, to complete a
loop. The photopolymer composition (24), conducting composition (26), the
primer (28), and/or plurality of nanoparticles may be applied to an
electrically conducting film as the substrate (22). This electrically
conducting film may include a thin film of aluminum or poly(3,4-ethylene
dioxy thiophene) and poly(styrene sulphonate) over ITO.

[0069]In one embodiment, the organic photopolymer is further defined as
poly(3-hexylthiophene) and the nanoparticles include titanium dioxide. In
this embodiment, the poly(3-hexylthiophene), the titanium dioxide, and
the dispersant are present in a weight ratio of about 1:1:0.25. Also in
this embodiment, the module (20) produces a light absorbance of from
about 0.36 to 0.47 absorbance units measured at a wavelength between
about 400 and 700 nanometers, wherein the light absorbance has a maximum
measured at a wavelength between about 550 and 650 nanometers, and
wherein the light absorbance is measured when the photopolymer
composition (24) is at a thickness of about 100 micrometers on the
substrate (22). Furthermore, in this embodiment, the module (20) produces
a light absorbance of from about 0.45 to 0.46 absorbance units measured
at a wavelength between about 550 and 650 nanometers. This evidences an
ability to selectively operate modules (22) at certain wavelengths to
maximize efficiency. The aforementioned light absorbance is illustrated
in FIG. 6. Without intending to be bound by any particular theory, it is
believed that the light absorbance illustrated in FIG. 6 represents
approximately a 30% to 38% increase in efficiency of the instant
invention as compared to its conventional counterpart. In various
embodiments, the module (20) produces a light absorbance of from about
0.35 to 0.48, from 0.36 to 0.47, or from, 0.37 to 0.47, absorbance units
measured at a wavelength between about 400 and 700 nanometers, wherein
the light absorbance is measured when the photopolymer composition (24)
is at a thickness of about 100 micrometers on the substrate (22).

[0070]Also in the aforementioned embodiment, the module (20) produces a
photoluminescence of from about 1275 to about 2300 photon counts per
second at a wavelength between 600 and 750 nanometers. This
photoluminescence is illustrated in FIG. 7. Without intending to be bound
by any particular theory, it is believed that the photoluminescence
illustrated in FIG. 7 represents approximately a 10 to 15% increased
output in the instant invention as compared to its conventional
counterpart. More specifically, an area under the curve in FIG. 7
corresponding to the instant invention is 10 to 15% greater than an area
under the curve corresponding to a conventional counterpart. This
increased output is believed to be indicative of increased exciton
dissociation and electron transport through a network of the TiO2
with minimized electron recombination with the holes in the organic
photopolymer.

[0071]In other embodiments, the module (20) has a 4 to 10 percent power
conversion efficiency. Power conversion efficiency is measured as a
function of current input to the module (20) compared with voltage output
of the same module (20), as is known in the art. In other words, power
conversion efficiency is a ratio of an amount of electric power generated
by the module (22) to a total amount of solar incident radiation on the
module (22).

[0072]Typically, power conversion efficiency is calculated using
illumination of 100 mW/cm2 with an AM 1.5 solar simulator. As is
known in the art, power conversion efficiency depends on three factors
including open circuit voltage (Voc) in V, short circuit current
(Isc) in mA cm-2, and a fill factor (FF). Open circuit voltage
results from built in voltage of the module (22) and is voltage across
the module (22) under illumination when no current is flowing i.e., when
the module (22) is in an open circuit condition. This is typically a
maximum possible voltage of the module (22). Short circuit current is a
current developed by the module (22) when under illumination at no load
or in a short circuit condition. Fill factor is the maximum power
obtained from the module (22) divided by the open circuit voltage
(Voc) and the short circuit current (Isc). Fill factor is
calculated using the following formula:

ff=Pmax/(Voc*Isc)=(Vmax*Imax)/Voc*Isc

wherein Pmax represents a point on an I-V curve of a module (22)
under illumination wherein a product of current and voltage is at a
maximum. This maximum power is denoted as Pmax. Corresponding
voltage and current are denoted as Vmax and Imax, respectively.
Using the aforementioned values and a known solar irradiation (Po),
power conversion efficiency can be calculated using the following
formula:

η=Pmax/Po*A

wherein A is the surface area of the module (22).

[0073]The instant invention also provides the method of forming the module
(20) first introduced above. The method includes the step of disposing
the photopolymer composition (24) on the substrate (22). In one
embodiment, the step of disposing is further defined as disposing the
photopolymer composition (24) on the substrate (22) using a printing
apparatus. The printing apparatus may be an inkjet printer, a laser
printer, a printing press, or any other printing apparatus known in the
art. In another embodiment, the step of disposing is further defined as
spraying the photopolymer composition (24) on the substrate (22). Of
course, the instant invention is not limited to the aforementioned
disposal techniques and may include any technique known in the art.

[0074]In another embodiment of the instant method, the photopolymer
composition (24) is further defined as a film and the step of disposing
the photopolymer composition (24) is further defined as applying the film
to the substrate (22). In this embodiment, the step of applying the film
to the substrate (22) may be further defined as melting the film on the
substrate (22). Alternatively, the film may be laminated on the substrate
(22).

[0075]The method may also include the steps of disposing the conducting
composition (26), the primer (28), and/or the electrode (30), on the
substrate (22). These steps may include disposing any or all of the
conducting composition (26), the primer (28), and/or the electrode (30)
in direct contact with the substrate (22). Alternatively, any or all of
the conducting composition (26), the primer (28), and/or the electrode
(30) may be disposed on the substrate (22) in indirect contact with the
substrate (22). In various embodiments, the method includes one or more
of the steps of disposing the conducting composition on the substrate,
disposing the primer on the conducting composition, and/or disposing the
electrode on the photopolymer composition.

[0076]The step of disposing the photopolymer composition (24), and/or the
steps of disposing the conducting composition (26), the primer (28),
and/or the electrode (30) on any other layer may be completed by any
means known in the art including, but not limited to, spin coating, brush
coating, spray coating, knife coating, and combinations thereof. The
photopolymer composition (24) may be disposed on the substrate (22) in
solid, liquid, or gaseous form. The conducting composition (26) and the
primer (28) may also be disposed on the substrate (22) in solid, liquid,
or gaseous form. The photopolymer composition (24), conducting
composition (26), the primer (28), and/or the electrode (30) may be
disposed on the substrate (22) by chemical means, mechanical means, or
through a combination of both chemical and mechanical means. More
specifically, any or all of the photopolymer composition (24), conducting
composition (26), the primer (28), and/or the electrode (30) may be
disposed on the substrate (22) as a matrix of dots using a printer. These
dots may be applied over a thin film of aluminum over which another
matrix of conducting dots are applied. The dots may be connected by thin
(nano-wide) wires which are connected in parallel at one end. It is also
contemplated that any of the photopolymer composition (24), conducting
composition (26), the primer (28), and/or the electrode (30) may be
encapsulated either partially or totally by another other portion of the
module (20). In one embodiment, the method includes the step of disposing
the electrode on the photopolymer composition via chemical vapor
deposition. The method may further include the step of applying a second
photopolymer composition to the substrate (22) and/or applying a second
substrate to the substrate.

EXAMPLES

Formation of the Instant Invention

[0077]A hybrid photovoltaic cell module (Module 1) is formed according to
the instant invention. Module 1 includes a substrate (22) and a
conducting composition (26) disposed on the substrate (22) as shown in
FIG. 13. More specifically, the substrate (22) is a 25 mm×25 mm
square glass (SiO2) sheet that includes a 150-200 nm thick coating
of the conducting composition (26) disposed thereon. The conducting
composition (26) includes indium tin oxide (ITO). The substrate (22) and
conducting composition (26) have a sheet resistance of approximately 8-12
Ohm. The substrate (22) including the conducting composition (26)
disposed thereon is commercially available from Delta Technologies of
North-Stillwater, Minn.

[0078]Before the substrate (22) is used to form Module 1, the substrate
(22) is immersed in an acetone bath for 10 minutes and then dried in a
stream of nitrogen. Subsequently, the substrate (22) is immersed in an
isopropyl alcohol (IPA) and/or ethanol bath for 10 minutes, washed with
deionized water, and again dried in a stream of nitrogen.

[0079]In addition to the substrate (22), Module 1 also includes a primer
(28) including poly(3,4-ethylene dioxy thiophene) and poly(styrene
sulphonate) disposed on the substrate (22). The primer (28) is in direct
contact with the conducting composition (26) as shown in FIG. 13. The
poly(3,4-ethylene dioxy thiophene) and poly(styrene sulphonate) are spun
at 3000 RPM for 60 seconds to form the primer (28) on the conducting
composition (26). After spin coating, the primer (28) is baked for 2
hours at 100° C. in a vacuum oven. The poly(3,4-ethylene dioxy
thiophene) and poly(styrene sulphonate) are commercially available from
Sigma-Aldrich of Allentown, Pa. Without intending to be bound by any
particular theory, it is believed that the primer (28) smoothes the
conducting composition (26) thereby reducing a chance of a short circuit
between positive and negative electrodes and also has a higher work
function (5.0 eV) than the conducting composition (26). It is also
believed that the higher work function facilitates transfer of holes from
the highest occupied molecular orbital of the poly-(3-hexylthiophene),
described in detail below, and improves charge transport between the
poly-(3-hexylthiophene) and the indium tin oxide.

[0080]Module 1 also includes a photopolymer composition (24) disposed on
the substrate (22) and in direct contact with the primer (28) as shown in
FIG. 13. More specifically, the photopolymer composition (24) is disposed
on the substrate (22) and in direct contact with the primer (28) by spin
coating at 100 rpm for 30 seconds and then at 2000 rpm for 45 seconds.
After spin coating, the photopolymer composition (24) is allowed to dry
for 24 hours at room temperature under vacuum. The photopolymer
composition (24) of Module 1 includes poly-(3-hexylthiophene) mixed with
TiO2 and a dendrimer. The poly-(3-hexylthiophene) is available from
Plextronics of Pittsburgh, Pa. and has a molecular weight of
15,000-20,000 g/mol. The poly-(3-hexylthiophene) is readily soluble in
most organic solvents and has a typical mobility of 0.1 cm2/Vs. The
TiO2 is a 30 nm TiO2 powder commercially available from MTI
Corp of Richmond, Calif., is 99.5% pure with crystalline structure, is
99.99% rutile, and is manufactured by a SOL-GEL process.

[0081]In addition, Module 1 also includes an electrode (30) disposed on
the substrate (22) and in direct contact with the photopolymer
composition (24), as shown in FIG. 13. The electrode (30) includes
aluminum (Al) that is vacuum evaporated on the top of the photopolymer
composition (24) for external connection.

Preparation of the Photopolymer Composition (24):

[0082]As set forth above, the photopolymer composition (24) includes
poly-(3-hexylthiophene) mixed with TiO2 and the dendrimer.

Preparation of the poly-(3-hexylthiophene) mixed with TiO2

[0083]The poly-(3-hexylthiophene) is mixed with the TiO2 in 1:1 ratio
by weight with xylene as a solvent to form a mixture. The mixture is
maintained at a temperature of about 50° C. in a temperature bath
and continuously stirred using an ultrasonicator. Subsequently, the
mixture is divided into a first part and a second part. An amount of the
dendrimer of the instant invention, described in detail below, is
introduced into the first part with continuous stirring. The final weight
ratio of the first part is 1:1:0.25 of poly-(3-hexylthiophene) to
TiO2 to dendrimer. The second part is then recombined with the first
part to form photopolymer composition (24).

[0084]Preparation of the Dendrimer:

[0085]The dendrimer is formed by reacting pentaerythritol (molecular
weight=136 g/mol) and hexahydropthalic anhydride (molecular weight=154
g/mol) over one hour in a ratio of 1:3, in a solvent of ethyl methyl
ketone (2-butanone), and at a temperature of from 130-140° C. The
temperature is maintained using a constant temperature bath of mineral
oil. Reaction of the pentaerythritol and hexahydropthalic anhydride is
exothermic and small amounts of toluene are typically added to control
the exotherm. After one hour, three moles of 2,3-epoxypropyl neodecanoate
(eq. wt.=250) are added to form the dendrimer and the exotherm is kept at
or below 150° C. The pentaerythritol, hexahydropthalic anhydride
and 2-butanone are commercially available from Sigma-Aldrich, Allentown,
Pa. The 2,3-epoxypropyl neodecanoate is commercially available from
Hexion Specialty Chemicals Inc. of Pueblo, Colo. under the trade name of
Cardura-N.

Formation of Comparative Example:

[0086]In addition to Module 1, a comparative module (Comparative Module 1)
is also formed but not according to the instant invention. Comparative
Module 1 is formed in exactly the same way as Module 1. However, the
photopolymer composition used to form Comparative Module 1 does not
include the dendrimer of the instant invention.

Analysis of Module 1 and Comparative Module 1:

[0087]After formation of Module 1 and Comparative Module 1, each is tested
to determine an amount of dispersion of the TiO2 in the photopolymer
composition using a scanning electron microscope commercially available
under the trade name JEOL JSM-6380LV, having a magnification range from
150 to 270,000, and scanning from 500 μm to 50 nm. The scanning
electron microscopy images are set forth in FIGS. 2-5.

[0088]Both Module 1 and Comparative Module 1 are also tested to determine
absorption measurements of the photopolymer compositions using an Agilent
8453 spectrophotometer. For reference, absorption measurements are taken
of the glass substrate by itself. To process the absorption measurements,
UV-Visible Chemstation software is used. The results of the absorption
measurements are shown in FIG. 6 wherein the light absorbance is measured
when the photopolymer composition is at a thickness of about 100
micrometers on the glass substrate.

[0089]In FIG. 6, the absorption spectrum for Module 1 includes two peaks,
one at 566 nm and other at 610 nm. The absorption spectrum for
Comparative Module 1 includes a single peak at 560 nm and a shoulder at
605 nm. Thus, these measurements indicate that through use of the
dendrimer of this invention, the absorption spectra is broadened towards
longer wavelengths and that inter-band absorption is increased, thereby
increasing efficiency of Module 1.

[0090]As shown in FIGS. 2-5, the scanning electron microscopy reveals
structural morphology and improved distribution and ordering of both the
TiO2 and the poly-(3-hexylthiophene) polymer in Module 1 as compared
to Comparative Module 1. More specifically, the scanning electron
microscopy indicates that the dendrimer of this invention increases the
dispersion of the TiO2 in the photopolymer composition in Module 1
as compared to the TiO2 in the photopolymer composition without the
dendrimer in Comparative Module 1. Without intending to be limited by
theory, it is believed that this increased dispersion contributes to the
increased efficiency of Module 1.

[0092]Without intending to be bound by any particular theory, it is
believed that the absorption of Module 1 can be attributed, at least in
part, to distribution and interaction between the TiO2 and the
poly-(3-hexylthiophene)polymer. It is believed that the presence of the
TiO2 lowers the poly-(3-hexylthiophene)polymer absorption due to a
disordered matrix. Inclusion of the dendrimer of this invention increases
overall absorbance and produces more pronounced absorbance peaks in
Module 1 as compared to Comparative Module 1. It is believed that the
absorbance peaks result from II-II* transitions indicating improved
exciton formation and ordering of the photopolymer composition. It is
also believed that increased inter-band absorption in Module 1 is
indicative of improved ordering of the photopolymer composition. Improved
ordering is thought to maintain interactions among polymer chains and
improve absorption effectiveness. Still further, the broadening of the
absorption spectra towards longer wavelengths in Module 1 is also though
to indicate improved ordering of the photopolymer composition due to
enhanced conjugation length and a shift of the absorption spectrum to
lower energies.

[0093]Additionally, both Module 1 and Comparative Module 1 are tested to
determine photoluminescence measurements of the photopolymer composition
using a FluoroMax-3 spectrofluorometer with excitation source of
wavelength 550 nm. The results of the photoluminescence measurements are
shown in FIG. 7.

[0094]The photoluminescence measurements are useful to evaluate a degree
of exciton dissociation, an amount of exciton recombination, and an
extent of charge transport. As is known in the art, excited electrons
return to a ground state and emit energy in the form of radiation. As is
also known in the art, dissociated electrons can recombine with adjacent
holes due to inefficient charge transport and lost the radiation. The
radiation can be detected using photoluminescence.

[0095]As shown in FIG. 7, the photoluminescence measurements indicate an
increase of photoluminescence in Module 1 as compared to Comparative
Module 1 due to improved exciton dissociation and electron transport
through a network of the TiO2 with minimized electron recombination
with the holes in the photopolymer composition. It is believed that this
increase is further indicative of the increased efficiency of Module 1.

[0096]The invention has been described in an illustrative manner, and it
is to be understood that the terminology which has been used is intended
to be in the nature of words of description rather than of limitation.
Obviously, many modifications and variations of the present invention are
possible in light of the above teachings, and the invention may be
practiced otherwise than as specifically described.